Braking mechanism



Feb. 2K0, 1940 f5 DlcK 2,190,979

BRAK ING ME CHANI SM Filed May 16, 1958 Mmmm - n INVENT OR.

^uamsmcm BY g u L l a ATTORNEY.

ritmes Feu-2c, 1940 UNITED sTA'rss I 'leirrlszrrl'v oFFlcE ration o! Delaware Louis, Mo., a corpo- Appumxnn my 1s, 1m, semmnfzoaisi io cmu. (ci. iss-152) My invention.. relates to braking mechanism and more particularly to brakes o! the two-shoe type which are positionedwithin the drum in end-to-end relation.

I One o! the objects of my invention is to prov duce a brake in which the adjacent ends of the shoes are actuated by two oppositely movable wedges* and the shoes are capable of acting as "forward shoes in both directions of rotation 'Another object oi' my invention is to produce an improved wedge-actuated brake in which two diametrically positioned wedges are adapted to be actuated by a single iluid motor and one of ll the wedges is adapted to be actuated by an auxiliary operating means independently o! the fluid motor.

Other objects of my invention will become apparent from the following description taken in I) connection with the accompanying` drawing in which Figure 1 is a side view, partly in section, of a brake embodying my invention; Figure 2 is `a cross-sectional view taken on the line 2-2 of Figure 1, the drum being omitted: Figure 3 I is a cross-sectional view taken on the line 3-3 o! Figure 1; and A:Figure iis a cross-sectional view taken on the line 4,4 of Figure 2.

. Referring to the drawing in detail, numeral I indicates the drum of the brake .assembly which is secured to a vehicle wheel and 2 the backing plate enclosing the open side of the drum 'ami` being secured to some convenient fixed part lnt the vehicle. Within the drum are two shoes 3 and 4 positioned in end-to-end` relation. The upper end of shoe 3 is notched for cooperation with an adjustable anchor pin 3 Aand the lower end of the shoe is formed with a straight surface for cooperation with an adjustable anchor l pin 3. 'I'he shoes are normally held in their o i position against their respective anchor pins by means of the springs l and I4 connected between the shoes.

The mechanism for actuating the shoes into engagement with the drum and which is an irnportant spaced apart yoke members Il and l2- which are positioned between the shoes in surrounding re- 'lation to the axis of the brake. The yoke mem:-

bers have secured therebetween a block I3 which lo carries a piston rod i4 ior actuation by a piston I5 mounted for reciprocation in a vertically positioned cylinder I3 interposed between the upper adjacent ends oi' shoes 3 and 4. -The external surface of the cylinder .has threaded thereon an l annular wedge/member Il which has formed on feat are oi my invention comprises two A diametrlcally opposite sides thereof, grooves I3 and Il inclined to the axis of the member. The upper end oi shoe I has pivotally mounted thereon a roller 2l for cooperation with groove I3 and the upper end of shoe rcarries a similar roller 6 2l for cooperation with groove I8, As best disclosed in Figure 3, roller 2| is pivotally mounted on' the end of a threaded rod 22 which is slidably mounted in a socket 23 in the endo! shoe 4. The rod and roller are adapted to be adjusted 10 relative to the end of the brakeshoe by means of a nut 24 which is threaded on the rod and abuts the shoe to hold the roller in its adjusted position. The outer surface of the nut is provided with serrations 25 for cooperation with a 16 spring detent 2B for holding the nut in its adjusted position.

'I'he piston I5 and cylinder I6 are held in their normal "oil` positions by means of springs 21 connected 'at their upper ends to opposite sides 20 of the cylinderA and at their lower ends to pins 23 on the yokemembers II and I2, the off positions being determined by the stop pins 29 carried by member I3. Fluid lunder pressure'is conveyed to the cylinder through a suitable con- 25 duit 3l which passes through an oversize opening 3|V in the backing plate whereby free movement ofthe cylinder will be permitted.

The lower portions of the yoke members i I and l2 `are provided with extensions 32 and 33 which 30 project between the lower adjacent ends of shoes 3 and 4. These projections support `a. pivot pin 34 uponwhich iis mounted a wedge member 35 positioned between the two projections. .The pivot pin,34 isreceived in an elongated slot 36 35 .in the wedge member in order to permit the wedge member to be moved relative to the pivot pin. The lower endoi shoe 4 carries a roller 31 ior cooperation with the groove 38 in one side of the wedge-member and the lower end of shoe 40 3 carries a roller 33 for cooperation with the groove 40 in the other side of the wedge member. The roller 33 is mounted upon a threaded rod v.4l which slidably projects into a socket 42 in the end of the shoe. The rod is adjusted relative ,.j,

to the shoe by the nut 43 which is provided with serrations 44 for cooperation with the holding detent 45.`

The wedge member 35 is held in its normallyV y inoperative position by means of spring 46 which 50 hasone end connected to a pin 41 on projection 32y of the yoke memberll and the other end connected to a pin 4`8 secured to thefbacking plate, thisllatter pin acting as a stop against which' spring 13 normally holdsthe yoke i I. n 55 ward shoes.

There is also shown auxiliary means for operating the wedge member 35 independently of the piston and cylinder which is employed to normally actuate the brake. This auxiliary actuat-y ing structure comprises a shaft 49 journaled in a bearing 50 carried by the backing plate, said shaftber 35 downwardly independently of the yokes due to the slotl35 in the lWedge. The shaft 49 is rotated by means of an arm 53, secured to theouter end of the shaft, and a connectingrod te leading to a suitable operating :member positioned at fan-remote point, as for example, the operators compartment of the vehicle.

When the drum isl rotating in the directionindicated by the arrow and fluid under pressure is supplied to cylinder l5, the cylinder will be forced upwardly and the piston within the cylinder will be forced downwardly. The upward movement of the cylinder will result inithe wedge member ii forcing the upper ends of the brake shoes apart and into engagement with the drum and the downward movement of piston i5 will cause the yoke members H and I2 to be forceddowiwardly and also the wedge member 35, thereby forcing the lower ends of the,y shoes apart and ,into engagement with the dum. As'the shoes are actuated into engagement with the drum,` shoe 3 willl anchor on pin 5 and shoe t will anchor on pin 1 due to the tendency of the shoes to move with the drum. Since the wedge member il? is moved by cylinder I6 and the Wedge member-35 is moved in the opposite direction by piston I5, the forces produced by the wedges to actuate the 'shoes into Iengagement with the drum will be equal. The yoke'members l i and I2 have sufiicient free movement to permit the wedge members to shift slightly with the ends of the shoes in order to adjust themselves between the ends of the shoes.

When the drum is rotating in the direction opposite that indicated by the arrow and fluid pressure is applied to the cylinder. and piston, the shoes will be forced into engagement with the drum in a manner already described but instead of anchoring on the anchor pins 5 and l'I they will anchor on the anchor pins 6 and 8. The shoes will now produce the saine amount of braking torque as they did in the otherdirection oi' rotation of the drum as both shoes act as for- Itis thus seen that the output of the brake is the same for either direction of rotation of the drum.

When it is desired to employ the auxiliary acy tuating means to actuate the brakes, rod 54 ils op- .erated to rotate shaftA 49 and cam 52 and thus force wedge member 35 downwardly between the lower ends of shoes 3 and 4. This will cause the shoes to be Aspreadfapart and engage with the drum. If the drum is rotating in the direction indicated by the arrow, shoe 3 will act as a Iorward shoe and anchor on pin 'l and shoe 4 will act as a reverse" shoe and be held in engagement with anchor pin il in the same manner Vas'arn ordinary two-shoe pivoted brake in which the shoes are pivoted at one pair ofadjacent ends and actuated at the other pair of adjacent ends. When the `drum is rotating in the ection opposite that indicated by the arrow arid the "auxiliary mechanism actuated, shoe 4 will anchor against pin l and become the "forward shoe andshoe I will be held in enga-gement with anchor pin 5 and act as a reverse shoe.

From the foregoing description it is apparent that I have disclosed a two-shoe brake and means for actuating the same which permits both of the brake shoes to act as forward shoes in both directions of rotation of the drum. The construction permits each pair of Vadjacent ends of the Ishoes to be actuated by a vwedge member andthe wedge members to be controlled by a single fluid motor which produces equal forces on the justment can be leasily accomplished by merely rotating a nut.

Being aware 0i the possibility of modifications in the particular structure herein described without departing from the fundamental principles of my invention, I do not-intend that its scope be limited except as set forth by the appendedv claims.

-Having fully described my invention, what I claimas new and desire to secure by Letters Patent of the United States is: i

l. In braking mechanism, a support, a rotatable drum,v two shoes positioned in end-to-end relation in the drum, means for anchoring the shoes, a wedge for actuating one pair of adjacent ends of the shoes, a second wedge foractuating the other pair of adjacent ends of the shoes, a member connected to one wedge and extending to a point diametricaily opposite said wedge and 'i adjacent the other wedge, and a iiuid motor havin the drum, means for anchoring the shoes, a

wedge for actuating'one pair of adjacent ends of the shoes, a second wedge for actuating the other pair of adjacent ends of the shoes, a yoke surrounding the axis of the brake and positioned between the shoes, means for pivotally connecting the first named wedge to the yoke, and a fluid motor connected to the other wedge and to the yoke at a point diametrically opposite the rst named wedge and adapted to move the wedges in opposite directions. 3. In braking mechanism, a support, a rotatable drum, two shoes positioned in end-to-end relationin the drum, means for anchoring the shoes, a wedge for actuating one pair of adjacent ends of the shoes, a second wedge for actuating the other pair of adjacent ends of the shoes, a member connected to one wedge and extending to a point diametrically opposite said wedge and adjacent the other wedge, a cylinder secured to the other wedge, a piston in said cylinder, and a piston rod carried by the member and cooperating with the piston.

4. In braking mechanism, a support, a rotatable drum, two shoes positioned in end-to-end relation in the drum and each extending over substantially 180 degrees of the drum, means for anchoring the shoes, a wedge for actuating one pair of adjacent ends of the shoes','a second wedge for actuating the other pair of adjacent ends of the shes, a member pivotally yconnected to one able drum, two shoespositioned in end-to-end relation in the drum, means for anchoring the shoes, a wedge for actuating one pair of adjacent ends of the shoes, a second wedge for actuating the other pair of adjacent ends of the shoes. a yoke surrounding the axis of the brake and positioned between the shoes, means for pivotally connecting one wedge to the yoke, a fluid motor connected to the other wedge and to the yoke at a point diametrically opposite the nrst named wedge and adapted to move the wedges in opposite directions, meanspermitting the pivotally connected wedge to be moved relatively to the l yoke, and' auxiliary actuating means for moving the pivotally connected wedge relative to the yoke.

6. In braking mechanism, a support, a rotatable drum, two shoes positioned in end-to-end relation in the drum, means for anchoring the shoes, a wedge for actuating one pair of adjacent ends of the shoes. a second wedge for actuating the other pair of adjacent ends of the shoes, a member connected to one wedge and extending to a point diametrically opposite said wedge and ad` jacent the other wedge, means cooperating with the member and the other wedge for moving said wedges in diametrically opposite vdirections and at right angles to the axis o! the drum, means permitting said rst named wedge to be moved independently of the member, and auxiliary actuating means comprising a rotatable cam for moving the iirst named wedge only.

7. In braking mechanism, a support, a rotatable drum, two shoes positioned in end-to-endI relation in the drum, an anchor pinfor each end o! each shoe, the ends of the shoes which cooper.- ate with the anchor pins in the normal forward direction of rotation of the drum being so associated with said pins that the end of the shoe is confined against radial movement but free to shift circumierentially away from the pin, a wedge for actuating one pair of adjacent ends, a second wedge for actuating the other pair of adjacent ends, a member connected ,to one of the wedges and extending to a point adjacent the other wedge, and means operating on said member and the other 'wedge for moving said wedges v in opposite directions.

8. In braking mechanism, a support, a rotatable drum, two shoes positioned in end-to-end relation in the drum, means for anchoring the shoes, a wedge for actuating one pair of adjacent ends of the shoes, a second wedge for actuating the other pair of adjacent ends of the shoes, rollers pivotally mounted on the ends of the shoes for cooperation with the wedges, a member connected to one wedge and extending to a point diametrically opposite said wedge and adjacent the other wedge, means cooperating with the member and4 the other wedge for moving said wedges in diametrically opposite directions and at right angles to the axis of the drum, and means for adjusting one of the rollers on each shoe relative to the end of the shoe on which it is mounted. i

9. In braking mechanism, a support, a rotatable drum, two shoes positioned in end-to-end relation in the drum, an anchor pin for each end of each shoe, the ends of the shoes which cooperate with the anchor pins in the normal forward .direction of rotation of the drum being so associated-with said pins that the end of the shoe is confined against radial movement ,but free to shift circumferentially away from the pin, a wedge for actuating one pair of adjacent ends, a` second wedge for actuating the other pair of adjacent ends, rollers pivotally mounted on the ends of the shoes for cooperation with the wedges, a member connected to one of the wedges` and extending to a point adjacent the other wedge, means operating on said member and the other wedge Ioriinoving said wedges in opposite directions, and means for adjusting the rollers which are mounted onthe ends of the shoes not conned against radial movement.

10. InV braking mechanism, a drum, two brake shoes positioned in the drum and having adjacent ends, fluid-operated' means lor actuating said shoe, said means comprising a movable cylinder positioned between the shoe ends, and an annular member adjustably mounted on the cylinder and provided with inclined surfaces on diametrically opposite sides thereof for 4cooperation with the.

shoe ends.

Bonus DICK. 

